Electronic storage device



2 SHEETSSHEET 1 E. s. HUGHES, JR

ELECTRONIC STORAQE DEVICE FEB. 10, 1953 Filed Dec. 31, 1951 INVENTORATTORNEY ERNEST S.HUGHE S JR.

nu vvvv Feb. 10, 1953 E. s. HUGHES, JR 2,628,309

ELECTRONIC STORAGE DEVICE Filed Dec. 31,;1-1951 2 SHEETS-SHEET 2 M P FIG2 INPUT f r Y I V V M P STAG 7 FIG 2A OUTPUT 01%? FIG 2s STAGE G 2COUTPUT I M P FIG 2D TRANsFER+ l I, l/ I,

+sov T 2 P4 INPUT 62 OUTPUT 5ov 61 6 es TRANSFER lllll IVVIV CANCELOUTPUT INVENTOR ERNEST SHUQHES JR.

ATTORNEY Patented Feb. 10, 1953 U N l TED STATES PATENT OFFICEELECTRONIC STORAGE DEVICE Ernest, Si, Hughes; n. Vestal- N... Y.;, n wto.

In national Business. Machines Corporation,

Ne ti-{ 19.57; Y;, a. corporation. 01; New York. gpplica-tionnecemher'31, 1951, Serial No. 264,295

.11. Claims. (01.. 2511-27) This inventionreletes to. electronic.storage devices, and its nrinelpaloblectsare to increa e the tabil tyof. such. devices: and... to: facilitate; the switching thereof.

Eleotronic storage devlcesofi the typecontemplated by the present. inveun are adapted. to assume stable on. anti ofiteonditionsand to. switchfrom one. eonditiouftorthe other in response to app ied volta e-pulses Astotagede vice of this; type mustlhayeisuffleient; sensitivity. so thatit; can berswitehed readily; under: the-control of the external pulsesandzitshouldialso be extremely stable during: the: mtervals. between.pulses. Engineers: tend to:- loole upon theserequirements as; beingsomewhat: contradictorm. and in designin hese storage de -ices; it iscustomaryto, effect; compromises wh ch; Wiil: Sat-' isfy the particularcondltionsz under; which. they will operate. The pre ent:inyentionrepresents: a somewhat different: approach to: the problem: ofdesignin electronicstorage devices-inthatrit. seeks to reconcilethedesirablerproperti saot:high stability and ease of switching;sor-thatztheaone will contribute to the. othl r. n13.12hfibtndt1idiot-'- fere with it.

In carrying out the foregoing bjects. I provid'e:

a novel storage: device; comprising; again or: rt rs valternate;statesotzmaaimunnandi minimum conductivity, the; second off thse in:- verters being contrclled bysthegfirst; togefiienwithr a cathodefollower controlledz ;bwthasecondainv verter for furnishing;- an;output; to; 3%. low-lure pedance load, a first diode for.-feedingibacle-a;

The double dicldeentry: arrangement: facilitates;

switching the" storage: device: under: thee control of the input-signal;

The principle of the" invention.laiparticularly useful when applledito;ring; circuits; although it. may be applied :also to individualstorage-units; In the form: of" ring circuit: which is'rzproposedherein,each stagerconstitutes: aa-storage device; of the characterJust-described;lneiudingiaepain of inverters, a cathode: followerrwhiohiservesan output tube and;aqpairvordiodesearrangedies a voltagecoincidence, switch- The voltages-rapeplied to thecoincidenceiswltchconsistcatered back voltage derivedjromfihecathodollowe1.; of t at e. nda-cemmonvinpptasi hic 1s; sunpliedconcurrently toall of thes'tages, The stagewhich; is, on is held latched in thatcondition by. the; coincidenceof theinput-signal and feedback voltage:polarities. A reversal of the in,- put signal: polarity destroys this"coincidence in the case of the stage which was on, thereby turning saidstage off and simultaneously turn.- lng the next stage on','whereupon1the aforesaid latching; action is repeated inthey case of the stagewhich is now on. This provides a simple, easy-andreliable way in whichto operate-a ring.

Other objectsandie'atures of theinvention will be: pointed. out; in thefollowing description and claims and illustrated inthe accompanyingdrawings, which disclose, by way of examples, the principle of theinvention and the best modes, whichhave: been contemplated, ofapplyingthat principle;

In the-drawings: v

Elgar lsa schematic showing of aring circuit which embodies theprinciple of' the invention.

Figs; 2 a;.2b;.2c and 2d are timing diagrams which. illustrate certainwaveforms,

Rig-3.15:2; composite ioscillog'raphic representation-.of three of. thewaveforn'i's shown in the templated by' the p'resent invention.- Thefirst stage; for) example, includesthe trlode inverters I 0 and? H anda'cathode-follower [2 Although the inverters In a and H are representedas separate tubes, they may, if desired, be placed in a single envelope;The grid l3"of the inverter I ll is-connected througha resistor l4 and adiode 31 (thelatter being" an element of a diode mixer 36 31" used forstarting purposes'only)" to the common" terminal I5 are positivecoincidence switch" comprising the diodes, l6. and I1. These diodes:are; generally germanium crystals, but

other. forms of. diodes may be used if desired. The common.t'er'minalilfi" of the diodes [Band H is connected through a resistor 20to" a sourceof, platevoltage represented asa +150 Voltsupply.

Theopposite.- terminal of. the diode" H-is connecteddiltectly tothecathodel8 of'thecathodeollower: ew-hieh cathoderis :connectedthrougha. load a resistor" ill" to; a: source of; negative: bias represented asa --50 volt supp1y.-. Theopposite terminal 0f: the: diode16?iS"0OI1II8CtEdi.tO-y92.11119 2| through which an input voltage waveis supplied to the ring system.

Fig. 2 illustrates the general type of voltage waveform which isemployed for the input signal. This voltage wave is supplied by asuitable source (not shown) to the point 22 on the line 2|, Fig. 1.Normally the input voltage, between points N and P on the wave, Fig. 2,is maintained at a steady positive value. At regular intervals 9.negative pulse is delivered, bringing the input voltage down to alimiting negative value, as indicated at the point M, Fig. 2. Betweenthe points M and N the voltage rises abruptly to its normal positivevalue. This type of voltage wave can be furnished by well-known meanssuch as a magnetic drum pickup feeding through a amplifier.

The plate 23 of the inverter i is connected through the parallelcombination of a capacitor 24 and resistor 25 to a point 26, which pointis connected through a resistor 21 to a negative bias supply (-50volts). .The grid 28 of the inverter II is connected through a resistor29 to the point 26. The arrangement is such that when the inverter I0 isconducting, the voltage at the plate 23 thereof is sufficiently low sothat the grid 28 of the inverter H is below cutoff. When the inverter I0is not conducting, the voltage of the grid 28 is raised above cutoff andthe inverter conducts.

When the first stage is off, the inverter I0 is cut off and the inverterII is conducting. The plate 30 of the inverter II is connected through aresistor 3| (by-passed by a capacitor 32) and a resistor 33 to anegative voltage source (-250 volts). The grid 34 of the cathodefollower i2 is connected by a resistor 35 to the junction of theresistors 3| and 33. With the inverter conducting, the voltage at theplate 30 thereof is sufliciently low so that the grid 34 of the follower2 is below cutoff. Under these conditions the cathode I 8 of thefollower |2 is held at a negative potential. Due to the voltage drop inthe resistor 20, the terminal I5 of the diode switch IG-l 1 ismaintained at such a value that the inverter I0 is held below its cutoffpoint.

Any of-the stages in the ring may be turned "on" by applying to the gridof the first inverter in that stage a positive pulse of a magnitudesumoient to start conduction. Thus, assuming that all of the stages areoff, and that it is desired to turn the first stage on, a positivestarting pulse may be applied from a suitable source (not shown) throughthe mixer diode 36 to the grid l3 of the inverter l0, thereby raisingthe voltage of the grid |3 above the cutofi value. When the tube |0starts conducting, the voltage of thetive potential or is returning toits normal positive potential following one of the periodic negativeinput pulses. The starting pulse is made sufiiciently long to insurethat the positive out-' put of the cathode follower 2 continues whilethe input line 2| is being restored to positive The resultingcoincidence of positive potential. voltages at the terminals of thediodes l6 and I1 4 insures that the grid l3 of the tube ID will re mainabove outooff and that the tube 0 will continue to conduct after thestarting pulse has ceased. The first stage thus is latched in its oncondition, with the positive feed-back voltage from the cathode followerl2 and the positive input voltage on line 2| serving to hold the firststage in "this condition. The cathode follower |2 in each stagefurnishes a positive output pulse during the time in which the stage ison, as will be explained more fully hereinafter.

The input voltage wave (Fig. 2) for operating the ring shown in Fig. 1consists of a normal positive potential which is interruptedperiodically by negative pulses. Each time one of these negative pulsesoccurs, the stage which has been on" is switched off and the next stageautomatically is switched on. Assuming that the first stage is on," thefirst negative pulse occurring at point M, Fig. 2, destroys thecoincidence of positive voltages at the switch |6|'|, with the inputline 2| now being at a negative potential. The grid l3 of the inverterI0 is thereby driven below cutoif, the inverter starts to conduct. andthe cathode follower I2 is cut off. The output of the cathode followerI2 now being negative, the grid 3 will not be'permitted to rise abovecutoff when the positive potential is restored to the input line 2| atpoint N, Fig. 2. Hence, the first stage is held in its off condition.

The second stage of the ring comprises the inverters 40 and 4| and thecathode follower 42, all of which are arranged in a manner substantiallyidentical with the first stage. The grid 43 0f the inverter 4| isconnected through a coupling capacitor 44 to the plate 30 of theinverter in the first stage. When the inverter starts to conduct, thevoltage of the plate 30 drops, causing a negative transfer pulse to beapplied through the capacitor 44 to the grid 43. The transfer signal isrepresented in Fig. 2d, which is a composite of all the transfer pulsesfrom stage to stagearranged on a single time base. At point M thetransfer pulse from stage I to stage 2 commences. As can be seen bycomparing Fig. 2d with Fig. 2, the width of l the negative portion ofthe transfer pulse is greater than the width of the negative input pulseM-N, Fig. 2. This insures that the inverter .4| will be maintainednonconductive until the input line 2| has been restored to its normalpositive potential. Therefore. the cathode follower 42 will furnish apositive output to the diode 45 of the coincidence switch 4546 while apositive potential is being reapplied to the other diode 46 of thisswitch.

' The output pulse of stage 2 (Fig. 2a) commences at point M, when thecathode follower 42 starts to conduct (this occurring at the instantwhen the inverter 4| is cut off). The inverter 40 does not'start toconduct 'until a coincidence of positive voltages occurs at switch45-'46, at which time the grid 41 is raised above cutoff, and the stageis latched in its on" condition. Conduction then takes place in the tube4|) and continues until point P, Fig. 2, when the next negative inputpulse occurs. At point P the positive coincidence is destroyed, drivinggrid 41 below cutofi.' The inverter 40 stops conducting, the inverter4lstarts to conduct, and the cathode follower 42 stops conducting. Theoutput of the follower 42 becomes negative, thereby ending the outputpulse of stage 2 at point P, Fig. 2a, and from this point onstage 2, ismaintained in its off condition.

As stage 2 is switched off, 'the following stage 5 automatically isswitched. mens;r mamsy on until the next negativeinput 'pul'se'turn 1tofif During the interval while each'staige is "jthe cathode followerthereof furnishes a po sitiv'eoutput voltage, v When-the 11th or finalstag icozn prising the inverters '53 and andthe cathode follower 52,Fig. l) "switched foff-J -a 'transfer p l la e t h jp e bithe inveter-r1 If th ne. is to e icrl ld. this t an f r. ul is communicatedthrough *ajc'apacitor '53 tothe r d flvq t in ert ll' x thefi t. ine byt nin the fir t see {f e-f t e r is o o n he 'f e b i k: th, fdm, the ls -sie w he; fi s a 'sbmi eii em cau n eac stage to -em'ain nitsfoiffco'miitiorr nt at art i l is li fairies v of the stages. The entirernrg I cancelled at any time by holding the put voltage-neg until. t e tans eririlsl l.

Fig. 3 is a compositethning iii irig the input voltagewave, t H wave andthe transferfs'ig'hal or a m'gle"stage, as they would be viewed on anos'pillosohe. 'Ihe curve 50 depicts one-cycle of "the-input voltagewave. Curve 6i representsth'e outputof a a'rtioular stage (stage 2, forexample), Cdzvet? is the transfer signal whichbassesfromstage i to stage2 as the former stage is switched off and the latter stage -i.s*switchedo'n. Tn-other words, the curve '62 shows the variation of "the voltageat the 'grid 33 of *the inverter M in stage 2.

After the input voltage 'st'ar'ts tofswlng'ne ative, at the point'G3-Fig. 3, and passes the cutoff value forthe inverterIQfFigIlfthe-ihverter ll starts to conduct. This produces a drop in thevoltage-atthe 'grid "#3, Eomihencing at point 65, Fig.3. When this'grid'voltagefcirops below the cutoff value for the-inverter i,;theoutput voltage of the cathode'follower 42, Fig. 1, commences to riseatpo'int 65, Fig. 3. The input voltage, curve 66, reaches its lowerjlirnit at point 65 and then commencesto rise. -Eventually, the rising;output voltage, carve GL- and the rising input voltage, curve till,reach-atom 6'! (Fig. 3) where they are 'suificientl positive" to hold'orlatch the inverter 'flfil'Fi'gi-"l-fin rte-eonductive'state. It will benoted that this latching action occurs before the negative-portion'of"the transfer pulse, curve 62, is dissipated. v

Fig. 4 illustrates schematically an individual storage unitutilizi'ng'the latch prin'ci'1'sle described hereiriabove. The triodeinverters H3 and H and the cathode follower 12am arranged andinterconnected in substantia1-Iy -the same manner as are thecorrespondingelements "in' a single stage of the ring circuit shown'inFig.1 In the present case, however, the grid 1-3 of "the inverter it isconnected through a resistor 14 to the common terminal 15 of adiodemixer cornprising the diodes it and 17. The-junctionlfi isconnected through a resistor 18 too. negative bias supply (50 volts).The opposite terminal of the diode i1 is connected to the output te'rminal E9 of the cathode follower 72. During the time when'thestorage'unit is on and the output voltage thereof is positive, thepotential of the grid i3 is held above cutoff, thereby latching theunit. At other times the grid 13 is held below its cutoh" potentialby-the negativebias supplyv 'When the storage unit shown in Fig. 4 is tobe employed in a diode matrix, ora similar network, to detect acoincidence of pulses-the input terminal 'of the mixer" diode. '76 isconnected to to conduct be'rer-stor hge'pmse. I

To cancel the 'sttihig' of th "tera'ge' uni-t s'hown in Fig i andthereby terminate the -pos'itive output pulse, a negative'cancelpulse-may be applied through a diode *to the 'plate 86 ot the inverterH, which plate is coupled to the-grid 8'! 'of the cathode follower 1 2.This'cuts 'ofitm follower i2 andchanges the output 'tlierof;from"aposi'- tive potential to a 'rieg'ative :pote'ntial, thus reizioving thepositive latching "Voltage from the rid 13 of the 'first inverter '10There bein no positive input voltageat this time, th grid '!3 assumesits normal negative potential, and the inverter 1 U-is u't eff.

An alternative methodof cancellingthestorage unit shown in Fig. 4 is toemploy-a 'ca'thodefollower 9?! as a cancel-tube for supply-ingapositivecancel pulse to the grid '83 :of -the-second inverter ii. When thisarrangement is employed, the

grid 83 is disconnected from the -50 volt'hias supply and iscohnected-ins'tghadl through a line as to the output terminal-92 -'ofthe cathode follower 99, which terminalisconnecteol in turn through theload resistor 9; of the' follower to a -75 volt bias source I A singlecancel tube such as fi 'fcan be employed to cancelas inany as ten latchunits in this manner. When the cancel tube is not cohdu'c'ti n'g, itscathode serves as abi'a's supply to 'thei arious storage units. I

The present retention, as may be bbsefved from the "aboveeisewsea embodments thereof is applicable" to storage 'iihifswh'ich "are adapted tosup 1y low-impedance,bower-consuming loads. It should be 'distihguished,thereforef'froih the type of stora'e'iinitsiwlfich are employed ine1eetromec6unters' and' th'e like, where the loads are negligible. Ineach or t ejsterageuviees illii'strated herein; the cathodic mutterfeedback stability "when neeeed tedeasetf switchir'igirom one'stameeenaitiento dfibth'er. The advantages of 'switchifii n this are"especially pronounced theease t me my (Fig. 1), wherein thep'ro'gressive la tching""afid-'unlatching of the stages" "will followinstantaheously the variations offa cemmonifieutvoltage Withoutany'adv'erseefie'ct up ifthe' ahilityofariy stage. The feature or biri gjaloliet ahc'el 'the iirig at any time by "holdihg th'e" {miut" vouagenegative is also very useful.

\Vhile "there have lbeeh s'htiwh and described and pointed out -thefundairihtal never features of the invention asappliedto-severalpreferred ernbo'difiintsthreof, itiwi-ll be understood thatvarious 'oniissibns and substitutions andfohanges in; the jfbrrn anddetails of the illustrated-devices and in=the"'-operationsm'ay bemade bythose skilled in th "art, without "departing from the spirit-of-the,e'rition. It=is"the-inthtion,therefore; to be h; tea-'omy-as"indiiiatedby" the scope of the follow n laims.

What is clairhedis:

1. 'An electronic storageeevme comprising first, seoond'anclt rd ele' Vndisoharge devices each having anput "cheater-a cohtrol electrode an"each being eearsteaatoassume altercontrol electrode thereof, meanscoupling the control electrode of said second electron discharge deviceto the output electrode of said first electron discharge device forcausing said second electron discharge device to assume a state ofconductivity opposite to that of said first electron discharge device,means coupling the control electrode or said third electron dischargedevice to the output electrode of said second electron discharge devicefor causing said third electron discharge device to assume a state ofconductivity opposite to that of said second electron discharge deviceand corresponding to the state of conductivity of said first electrondischarge device, a voltage coincidence switch having an output terminalconnected to the control electrode of said first electron dischargedevice and having a pair of input terminals through which voltages maybe separately impressed upon the last-mentioned control electrode, oneof said switch input terminals being connected to the output electrodeof said third electron discharge device, and an input line connected tothe other of said switch input terminals for applying thereto an inputvoltage that varies intermittently between predetermined limits, wherebythe state of conductivity of said first electron discharge device iscontrolled in response to the relationship between said input voltageand the output voltage of said third electron discharge device.

2. An electronic storage device comprising first and second electrondischarge devices each having an output electrode and a controlelectrode and each being adapted to assume alternate states of maximumand minimum conductivity in response to variable voltages impressed uponthe control electrode thereof, means coupling the control electrode ofsaid second electron dis charge device to the output electrode of saidfirst electron discharge device for causing said second electrondischarge device to assume a state of conductivity opposite to that ofsaid first electron discharge device, a cathode follower having anoutput electrode and a control electrode, means coupling the controlelectrode of said cathode follower to the output electrode of saidsecond electorn discharge device means including a diode for couplingthe output electrode of said cathode follower to the control electrodeof said first electron discharge device, an input conductor forsupplying to said storage device an input voltage that variesintermittently between predetermined limits, and a second diode forconnecting said input conductor to the control electrode of said firstelectron discharge device, whereby the state of conductivity of saidfirst electron discharge device is determined by both the input voltageand the output voltage of said cathode follower.

3. An electronic storage device comprising a first inverter adapted toassume alternate states of maximum and minimum conductivity, 2. secondinverter adapted to assume alternate states of maximum and minimumconductivity, said second inverter being coupled to and controlled bysaid first inverter so that said inverters are in opposite states'ofconductivity, feedback means including a. cathode follower and a diodefor applying a signal from the output side of said second inverter tothe input side of said first. inverter, and additional input meansincluding a second diode for independently applying a separate inputsignal to said first inverter.

4. An electronic storage device comprising a first inverter having acontrol electrode and 8 adapted to assume alternate states of maximumand minimum conductivity in response to predetermined voltages ofdifiering polarities impressed upon said electrode, a second invertercontrolled by said first inverter, a cathode follower controlled by saidsecond inverter for furnishing output voltages of differing polaritiesin accordance with the conductive state of said second inverter, inputmeans including a first diode for applying to said control electrodeinput voltages of varying values, and means including a second diodecoupling said control electrode to said cathode follower for applying tosaid electrode a feedback voltage which varies between predeterminedlimits of difiering polarities depending upon the conductive state ofsaid cathode follower, whereby the conductive state of said firstinverter is controlled by said input voltage and said feedback voltage.

5. An electronic storage device comprising a first inverter having acontrol electrode and adapted to assume alternate states of maximum andminimum conductivity in response to predetermined voltages of differingpolarities im pressed upon said electrode, a second inverter controlledby said first inverter, a cathode follower controlled by said secondinverter for furnishing output voltages of differing polarities inaccordance with the conductive state of said second inverter, an inputconductor for supplying to the storage device input voltages of varyingmagnitudes and polarities, and a coincidence switch including a pair ofdiodes respectively connected to said input conductor and to saidcathode follower for latching said first inverter in one of itsalternate conductive states when both the input voltage and the cathodefollower output voltage are of a given polarity.

6. An electronic storage device comprising a first inverter having acontrol electrode and adapted to assume alternate states of maximum andminimum conductivity in response to predetermined voltages of differingpolarities impressed upon said electrode, a second inverter controlledby said first inverter, a cathode follower controlled by said secondinverter for furnishing output voltages of differing polarities inaccordance with the conductive state of said second inverter, an inputconductor for supplying to the storage device input voltages of varyingmagnitudes and polarities, and a diode mixer including a pair of diodesrespectively connected to said input conductor and to said cathodefollower, whereby said first inverter is caused to change its conductivestate in response to a change of input voltage polarity and isthereafter maintained in such conductive state by the output voltagefrom said cathode follower.

7. An electronic ring having a plurality of stages and means forsupplying a common input signal thereto, said ring comprising, in eachof said stages, a pair of inverters each adapted to assume alternatestates of maximum and minimum conductivity, with the relationshipbetween said inverters being such that the conductive state of the firstinverter normally causes the second inverter to assume an oppositeconductive state, input means for each stage including a pair of diodesarranged in a coincidence switch for causing the first inverter toassume a given state of conductivity only when the voltages respectivelyapplied to said diodes are both of a given polarity, and an output meansfor each stage including acathode follower controlled by the secondinverter and coupled through one of said diodes to the first inverterfor supplying a feedback voltage to said first inverter, said commoninput signal supply means being coupled through the other of said diodesto said first inverter, whereby each stage is maintained in apredetermined condition as regards the conductive states of itsinverters so long as the common input signal and the feedback voltagefor that stage are of a, given polarity and is switched to the oppositecondition when the polarity of the input signal is reversed, said ringalso comprising an individual transfer means between each pair ofadjacent stages so that the switching of one stage causes the next stageto be switched.

8. A ring as defined in claim 7, wherein said transfer means serves tocouple the second inverter of one stage to the second inverter of thefollowing stage in such fashion that a reversal of the one inverterproduces an opposite reversal of the other inverter.

9. An electronic ring having a plurality of stages and means forsupplying a common input signal thereto, said ring comprising, in eachof said stages, a first tube means controlled by said common inputsignal means for assuming alternate states of maximum and minimumconductivity in response to variations of the input signal, a secondtube means controlled by said first tube means for assuming a conductivestate opposite to that of said first tube means, and feedback meansincluding a cathode follower coupling said second tube means to saidfirst tube means for maintaining said first tube means in the state ofconductivity which said first tube means has assumed in response to saidinput signal.

10. An electronic storage device for use in combination with a voltagecoincidence switch which is adapted to furnish a given output voltage inresponse to simultaneous input voltage pulses of like polarity appliedto said switch, said device comprising a first inverter having an inputside thereof connected to the output side of said coincidence switch, asecond inverter controlled by said first inverter, said inverters beingadapted to assume opposite states of maximum and minimum conductivity inresponse to the output of said coincidence switch, and a cathodefollower controlled by said second inverter for furnishing an outputvoltage as determined by the conductive state of said second inverterand for applying a feedback voltage to the input side of said firstinverter.

11. An electronic storage device as defined in claim 10, which includesa diode mixer so arranged in relation to said first inverter as to mixthe output voltage from said coincidence switch and the feedback voltagefrom said cathode follower.

ERNEST S. HUGHES, JR.

No references cited.

